Fireproof fabric and process of producing the same



To all whom it may concem:

UNITED CECIL L. SAUNDERS, GEORGE C. STANLEY, AND CHARLES W. BENNETT, 0FITHACA, NEW YORK.

EIEEr ooE FABRIC AND PROCESS 0E rnonnome THE SAME.

No Drawing.

Be it known that we, CECIL L. SAUNDERS, GEORGE C. STANLEY, and CHARLESV. BEN- NETT, all citizens of the United States, residing at Ithaca, inthe county of Tompkins and State of New York, have invented certain newand useful Improvements in" Fireproof Fabrics and Processes of Producingthe Same; and we do hereby decla're the following to be a full, clear,and exact description of the invention, such as A will enable othersskilled in the art to which it appertains to make and use the same.

This invention relates to a composition of matter, anda' method ofproducing the same which is applicable to the fire proofing of fabricsin general, and especially the fire proofing of aeroplane Wings.

The object of the invention is to provide a composition and a methodwhich is less costly, and more eflicient in practice than thoseheretofore proposed.

lVith this and other objects in View the invention consists in the novelcomposition of matter, and in the steps and combinations of steps forproducing the same, all as will be more fully hereinafter disclosed andparticularly pointed out in the claims.

In order that the precise invention may bethe more clearly understood,it'is said It is well known that the fabrics from which aeroplane wingsare produced are often subjected to fire risks, and that it is verydesirable indeed to so fire proof said fabrics without destroying theirstrength that should they become ignited, the flame will not spread andthe aviator may thereupon reach a landing in safety.

It is also .well known that it is ery desirable to coat fabricsin'general with a fire proofing material, having the above mentionedcharacteristics, but in all of the materials and'methods with which weare acquainted, various objections exist.

That is to'say, prior processes either rot the fabrics, or the flameswill spread unduly, or it is so expensive to apply the coating that theyhave not proved satisfactory in service. Especially has it been found inthe prior processes that the fire proofing coating, whatever it may be,is easily washed out, so that after the .fabric has been 'subjected toserious wettings, its fire proofing qualities are greatly deteriorated.

Further, ithas been found in practice that Specification of LettersPatent.

Application filed October 13, 1919.

Patented Nov. 9, 1920.

Serial No. 330,384.

cotton, is first boiled in water, to remove.

the size, and then treated with a weak solution of hydrofluoric acid,say about two parts in one hundred parts of water, as by dipping thesaid fabric for thirty minutes in the solution, and if it is thenwashed, and brought to a semi-dry state, the fabric will be found not tobe weakened at all, but even strengthened to a degree.

Its pores will also be found to be so open that it will readily take thefire proofing solution.

After the above mentioned treatment with hydrofluoric acid, we next maypass the fabric through a solution of sodium stannate, preferably havinga specific gravity of 1.075. The .fabric is subjected to this lastmentioned solution for about say one half minute, or somewhat longer,whereupon it is wrung out and dried. We then pass the said fabricthrough a solution of ammonium sulfate, preferably having a specificgravity of about "1.045 and it is subjected to this last mentionedsolution for about the same time as just stated, or about say one minuteor a little longer.

This said hydrated oxid of tin Sn6 1wH O is in an exceedingly finelysubdivided condition, and it functions as a most eflicient fire proofingmaterial or agent for preventing the spreading of flame, whether it beapplied to fabrics, to .the fibers before the fabrics are made up,or-even to wood. Whereas, the above treatment is found to monia come beefficient-in practice, our preferred process consists in the followingWe take a mixture of sodium stannate and of'ammonium sulfate, as abovementioned, but preferably in the solid condition, and grind themtogether until the fumes of amoff, whereupon we add to'the mixture anysuitable varnish. This varnish may be of a gummy or resinous nature, orit may be the Well known varnish that is now used on aeroplane Wings,which is a cellulose nitrate, or a cellulose acetate. After the varnishis thus mixed with the above reagents, the grinding is continued untilwe have produced a thorough and intimate mixture of the varnish, and thehydrated tin oxid that is produced by the reaction during the grindingoperation.

As this reaction cannot, under the circumstances, be a completereaction, the varnish will be thus intimately mixed'not only with thehydrated tin oxid, above mentioned,

but there will also be present some am-- monium sulfate, as Wellas somesodium stannate, and undoubtedly some sodium sulfate too, all of whichingredients are good fire proofing reagents. The presence of the am-.nfonium ionundoubtedly has a good effect in causing a thoroughincorporation of the hydrated tin oXid into the fibers of the fabric,when the varnish containing said ingredients is applied thereto.Especially will this incorporation be very thorough if the fabric hasbeen previously treated with the hydrofluoric acidsolution abovementioned.

The varnish, whether it be a resinous one or one having a cellulosebase, after being thus emulsified, so to speak, with the fire proofingsubstances above mentioned, conbe applied. Further,

stitutes an article of commerce in itself, and wewish it to bedistinctly understood that this invention relates broadly to such acomposition no matter to what substances it may although this saidvarnish. may be made by other processes, than that mentioned, yet, weprefer to produce the varnish in the manner above disclosed because itis an efiicient way to import into the varnish a number of'fire proofingagents which serve, together with the former treatment of the fibers, toso thoroughly impregnate the same that in practice the product is foundto resist fire to a degree much higher manufacture comprising a= fabrichaving its fibers coated with a fire proofing compound comprising ahydrated oxid of tin and ammonium sulfate, substantially as described.

2. The herein described new article of manufacture comprising a fabrichaving its fibers coated with a fire proofing compound comprising avarnish havin therein a hydrated oxid 0 tin and ammonium sulfate,substantially as described.

3. The process of rendering cotton fibers more easily impregnated withsodium stannate which consists in boiling said fibers in water, treatingthe boiled fiberswith a solution of commercial hydrofluoric acid havinga strength of substantially two parts of acid to 100 parts of water,washing said'fibers; and bringing them to a semi-dry state,substantially as described.

4c. The process of fireproofing fabrics which consists 1n first treatingsaid fabrics with hydrofluoric acid and then coating their fibers with amaterial containing a hydrated oxid of tin, substantially as described.

incorporated- 5. The process of fire proofing fabrics which consists in.first treating said fabrics with hydrofluoric acid and then coatingtheir fibers with a materialcomprising a varnish,

containing a hydrated oxid of tin, substantially as described. 5

6. The process. of fire proofing fabrics which consists in firsttreating said fabrics with hydrofluoric acid and then coating theirfibers with a material comprising a varnish, containing a hydrated oxidof tin; and sodium stannate, substantially as described.

In testimony whereof we aflix our signatures.

CECIL L. SAUNDERS. GEORGE o. STANLEY. CHARLES w. BENNETT.

